Technical Field
The following description relates to aspects of an image forming apparatus configured to supply toner from a process unit to another process unit, and a method and a computer-readable medium for controlling the image forming apparatus.
Related Art
As a problem with an electrophotographic image forming apparatus configured to bring a cleaner into contact with a photoconductive body, it has been known that insufficient amount of toner at a contact portion between the photoconductive body and the cleaner is likely to cause an abnormal noise (i.e., so-called “squeaking”) due to friction between the photoconductive body and the cleaner. For instance, in an image forming apparatus configured to perform color printing, there may be a case where monochrome printing is consecutively performed with no other toner cartridge but a toner cartridge for monochrome printing being attached to the apparatus. In such a case, no toner image is formed in any process units other than a process unit for monochrome printing. Therefore, in each of the other process units, the contact portion between the photoconductive body and the cleaner is likely to hold little toner.
As an example of techniques for supplying toner to the contact portion between the photoconductive body and the cleaner, the following technique has been known. That is a technique to transfer toner developed on a photoconductive body in a first process unit onto an intermediate transfer belt, and reversely transfer the toner from the intermediate transfer belt to a photoconductive body of a second process unit by applying in the second process unit a reverse transfer bias having a polarity opposite to a polarity of a transfer bias for printing on a sheet.